Going to try this. What the hell, simple to do and un-do. Like the Power wire. It seems maybe resistors have a play in other places. Can I use one on my gas tank to resist sucking up so much fuel from it?

 

Do the advanced tune... you have more options

 

so is the same trans that the V6 has? Pics would be good too!

 

ive done the resistor mod. i also have a shift kit and i drive around with tow haul on. shifts nice when cruising, but when i jump on it, it really kicks. not as good as a tuner but only cost me the price of the shift kit and a res. i had laying around.

 

06dak287, Can you take some pictures of give some more info. Maybe a thorough DIY? Did you attach the resister and replug in the connector?

 

DJsilver,
Interesting mod, Ive been looking for a long time.
The 545rfe locks into 5th at 42 mph, ( not high enough in spped ).
It should lock in at about 62 mph. But the main problem is that to kick it back into forth when reaching a hill or something, we must press too far on the gas pedal, at then when it does kick into 4th or 3rd, our truck screams and then we got to let go alittle, then she shifts into 5th in no time. Between 42 and 60 mph, its really not a pleasant transmission.
The back shift is not sensible enough to our foot.
In Tow haul mode, the transmission shifts at a higher rpm ( in up-shifting), but the back shift is even worse. It stays locked into gear even longer. This is to save transmission life, and to prevent shifting and back-shifting too often.
Did you notice with your resistor, if the back-shift was more sensitive to your foot pedal. ( between 45 and 60 mph aprox. ) Would it back-shift alittle easier, with alittle less effort, or do you still half to squeez the pedal down way far??.
Im thinking of bringing two wires inside my truck, ( solder two ends at the trans plug inderneath ) and from inside my truck, try the 2.2 K ohms, maybe a 3K ohms, or even a 1.5K ohms and inderstand exactly what this does, and find the correct one.
But if it does not correct the back-shift sensitivity, then Im not sure its the cure.
What would help on all these trucks is a 4.10 diff ratio. The engin would be so happy, under alot less load at 50 - 65 cruising speeds.
On a perfect straight high-way, 3.55 is Ok, but in the country roads, its really to tall.
Keep in touch

Dan
--04 5.7 Durango--

 

Dans,
The mod changes the shift points but not the pattern. That's built into the controller. In casual driving mine now shifts to 5th around 50mph up to around 65mph depending on how I'm driving. In casual driving it will drop back to 4th without too much drama but I haven't towed anything since the change and don't know how much difference it'll make under load. When I have towed before the mod, I found the tow/haul mode too late in upshifting and too violent when downshifting. I ended up running in normal mode and modulating the pedal to force the shifts. You're idea about running wires to a convenient location to mount a resistor is a good one.

 

djsilver
Your explanation of the tow/haul is exact. I only use it at 62 mph and higher, sometimes when Im not even towing, just to get the extra couple hundered rpms to keep my speed in the hills.
These engins have to rev min 1800 rpm to be happy, I think. And at 2000 rpm, your still efficiant, because you're on the engins cams, and this is where you are most efficient ( rpm vs Hp vs fuel )
Ill try the mod in a couple of weeks, when I get the truck up for an oil change, and let you know.

Ever hear of a unit to activate the throttle body quicker. I believe that since its 'drive by wire', the throttle body itself does not open 100% below maybe 2500 rpm or so. This robs 0-60 feet times on a drag start.



Dan
04 5.7 durango